This invention relates generally to turbine apparatus, and more particularly to an improved gas turbine blade construction having means for hydrogen cooling the blade.
In a conventional gas turbine engine generally comprising an air compressor, combustion products generation means, a turbine wheel, and a duct connecting these elements in serial fluid flow relation, the high temperature of the combustion products calls for the use of cooling means for the turbine wheel. The cooling means conventionally comprises a conduit receiving air bled from the compressor and conveying it to the turbine wheel, the conduit being spaced from the duct for the combustion products to minimize heat exchange therewith. The engines of the above-mentioned type are complicated and expensive to construct and maintain. They are also open to the objection that parts frequently fail due to high stresses resulting from wide differences in expansion and contraction, particularly during the transient phases of operation.
Furthermore, the continued development of hypersonic propulsion engines is leading toward the use of hydrogen fuel and stoichiometric combustion temperatures. Due to material limitations, engine components exposed to these high temperature environment must be cooled. Cooling the turbine presents unique problems in that the cooling system must operate in a high centrifugal field.
As heretofore mentioned the use of air for cooling the turbine has been the technique utilized to date. However, as temperatures increase greater percentages of air must be extracated from the cycle for cooling purposes which tends to decrease overall cycle performance.